1. Field of Invention
The present invention is generally related to an apparatus having cutter elements for destroying documents such as paper sheets. In particular, the apparatus comprises a mechanism for advancing articles from a stack in a tray into the cutter elements for shredding.
2. Background
A common type of shredder has a shredder mechanism contained within a housing that is mounted atop a container. The shredder mechanism typically includes a series of cutter elements that shred articles such as paper that are fed therein and discharge the shredded articles downwardly into the container. An example of such a shredder may be found, for example, in U.S. Pat. No. 7,040,559.
Prior art shredders have a predetermined amount of capacity or amount of paper that can be shredded in one pass between the cutter elements. Typically, the sheets of paper are fed into the shredder mechanism manually. Thus, when an operator needs to shred, he or she can only shred a number of sheets of paper by manually inserting one or more sheets one pass at a time. Examples of such shredders are shown in U.S. Pat. Nos. 4,192,467, 4,231,530, 4,232,860, 4,821,967, 4,986,481, 5,009,410, 5,188,301, 5,261,614, 5,362,002, 5,662,280, 5,772,129, 5,884,855, and 6,390,397 B1 and U.S. Patent Application Publications 2005/0274836 A1, 2006/0179987 A1, 2006/0179987 A1, 2006/0249609 A1, and 2006/0249609 A1, which are all hereby incorporated by reference in their entirety.
Other shredders are designed for automatic feeding. The shredder will include a bin in which a stack of documents can be placed. A feeding mechanism can then feed the documents from the stack into the shredding mechanism. This type of shredder is desirable in an office setting for productivity reasons, as the user can leave the stack in the bin and leave the shredder to do its work. With manual feed shredders, the user would have to spend time feeding smaller portions of the stack manually, thus taking away from productivity time.
Furthermore, sensing devices alert a user to safety or issues which may affect the performance of the shredder. For example, the bin being full of shredded paper or an amount of paper queued or inserted for shredding may be determined. However, such sensors tend to be mechanically limited, and fail to dynamically determine performance characteristics. Examples of such devices are shown in U.S. Patent Application Publications 2005/0274836 A1 to Chang and 2006/0249609 A1 to Huang. Rexel, an ACCO Brands Company, also has a bulk autofeed shredder (e.g., Product Code 2101998) for auto-shredding documents. Using sensors to cooperatively determine information related to shredding in an auto-feed shredder would further improve shredding performance.